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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

38169 results found.

  1. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  2. IBAS Alert n.10856: not a GRB
  3. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  4. EP240816b: KAIT optical upper limit
  5. GRB 240814B: GRBAlpha detection
  6. Fermi trigger No 745501396: Global MASTER-Net observations report
  7. EP EP240816b: Global MASTER-Net observations report
  8. EP240816b: TRT optical upper limit
  9. Fermi GRB 240814A: Global MASTER-Net observations report
  10. Fermi GRB 240814C: Global MASTER-Net observations report
  11. Fermi trigger No 745306088: Global MASTER-Net observations report
  12. GRB 240814C: Fermi GBM Final Real-time Localization
  13. Fermi GRB 240814B: Global MASTER-Net observations report
  14. GRB 240812B: SVOM/GRM observation
  15. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  16. GRB 240814B: Fermi GBM Final Real-time Localization
  17. GRB 240814A: Fermi GBM Final Real-time Localization
  18. Fermi trigger No 745220784: Global MASTER-Net observations report
  19. Konus-Wind detection of GRB 240811A
  20. Konus-Wind detection of GRB 240810A
  21. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  22. GRB 240809A: Correction to the VLA source position in GCN 37158
  23. GRB 240810A: SVOM/GRM observation
  24. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  25. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  26. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  27. GRB 240809A: ATA radio non-detection
  28. GRB 240812D: Fermi GBM Final Real-time Localization
  29. GRB 240812C: Fermi GBM Final Real-time Localization
  30. GRB 240809A : RAPAS follow-up observations
  31. GRB 240809A: VLA detection
  32. GRB 240809A: ALMA detection
  33. IPN triangulation of GRB 240810A (short)
  34. GRB 240811A: Swift-BAT refined analysis
  35. GRB 240809A: Swift-BAT refined analysis
  36. EP240807a: PRIME H-band upper limits
  37. GRB 240812B: AstroSat CZTI detection of a long burst
  38. GRB 240811A: Bassano Bresciano Observatory upper limit
  39. GRB 240811A: Swift-XRT refined Analysis
  40. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  41. GRB 240811A: Swift/UVOT Upper Limits
  42. EP240801a: Assy-Turgen optical observations
  43. Fermi GRB 240810A: Global MASTER-Net observations report
  44. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  45. GRB 240812A: Fermi GBM Final Real-time Localization
  46. GRB 240811A: LCOGT Optical Upper Limit
  47. GRB 240811A: Enhanced Swift-XRT position
  48. GRB 240811A: Upper limits with Mephisto
  49. Konus-Wind detection of GRB 240809A
  50. Fermi trigger No 745057312: Global MASTER-Net observations report
  51. Swift GRB 240811A: Global MASTER-Net observations report
  52. GRB 240811A: Swift detection of a burst
  53. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
  54. GRB 240810A: Fermi GBM Final Real-time Localization
  55. GRB 240809A: REM detection of the optical afterglow
  56. GRB 240809A: Bassano Bresciano Observatory optical observations
  57. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  58. GRB 240809A: Conclusive redshift from VLT
  59. Fermi-LAT gamma-ray observations of IceCube-240808A
  60. GRB 240809A: KAIT optical observations
  61. GRB 240808A: AstroSat CZTI detection
  62. GRB 240809A: GIT afterglow observations
  63. GRB 240809B: MAXI/GSC detection
  64. GRB 240809A: Swift/UVOT Detection
  65. GRB 240809A: Tentative redshift from NOT
  66. GRB 240809A: Swift-XRT refined Analysis
  67. IPN triangulation of GRB 240807A / EP 240807a
  68. X-ray Transient EP240807a: PRIME near-infrared upper limits
  69. Swift GRB 240809A: Global MASTER-Net observations report
  70. GRB 240809A: JinShan optical observations
  71. GRB 240809A: Enhanced Swift-XRT position
  72. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  73. GRB 240809A: SVOM/GRM observation
  74. GRB 240808A: SVOM/GRM observation
  75. GRB 240807A: SVOM/GRM observation
  76. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  77. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  78. GRB 240807B: AstroSat CZTI detection of a short burst
  79. IceCube Alert 240808.27: Global MASTER-Net observations report
  80. EP EP240807a: Global MASTER-Net observations report
  81. EP EP240806a: Global MASTER-Net observations report
  82. GRB 240801A: GRBAlpha detection
  83. GRB 240807B: Fermi GBM Final Localization
  84. GRB 240710B: VZLUSAT-2 detection
  85. GRB 240805A: ATCA Radio Upper Limits
  86. Fermi trigger No 744761058: Global MASTER-Net observations report
  87. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  88. EP-WXT trigger 01709018832: KAIT optical observations of the star flare
  89. EP240802a/GRB240802A: KAIT optical upper limit
  90. GRB 240720B: VZLUSAT-2 detection
  91. GRB 240710A: VZLUSAT-2 detection
  92. GRB 240807A: Fermi GBM Final Localization
  93. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  94. GRB 240805B: GIT optical upper limit
  95. EP240806a: KAIT optical observations
  96. GRB 240805B: Swift-BAT refined analysis
  97. GRB 240805A: Swift-BAT refined analysis
  98. Fermi trigger No 744629911: Global MASTER-Net observations report
  99. EP240804a (GRB 240804B): NOT optical observations
  100. EP240806a: LCOGT optical counterpart detection

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